Fixing regex bug

Added handlebars support test
Contribution by https://github.com/fatalerrorx

Jint.Tests/Jint.Tests.csproj

@@ -99,6 +99,9 @@
   <ItemGroup>
     <Service Include="{82A7F48D-3B50-4B1E-B82E-3ADA8210C358}" />
   </ItemGroup>
+  <ItemGroup>
+    <EmbeddedResource Include="Parser\Scripts\handlebars.js" />
+  </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <Import Project="$(SolutionDir)\.nuget\NuGet.targets" Condition="Exists('$(SolutionDir)\.nuget\NuGet.targets')" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 

Jint.Tests/Parser/JavascriptParserTests.cs

@@ -21,6 +21,7 @@ namespace Jint.Tests.Parser
         [InlineData("mootools.js", "1.4.5")]
         [InlineData("angular.js", "1.2.5")]
         [InlineData("JSXTransformer.js", "0.10.0")]
+        [InlineData("handlebars.js", "2.0.0")]
         public void ShouldParseScriptFile(string file, string version)
         {
             const string prefix = "Jint.Tests.Parser.Scripts.";

Jint.Tests/Runtime/EngineTests.cs

@@ -9,6 +9,7 @@ using Jint.Parser.Ast;
 using Jint.Runtime;
 using Xunit;
 using Xunit.Extensions;
+using System.Net;
 
 namespace Jint.Tests.Runtime
 {
@@ -31,7 +32,6 @@ namespace Jint.Tests.Runtime
 
         private void RunTest(string source)
         {
-
             _engine.Execute(source);
         }
 
@@ -839,5 +839,31 @@ namespace Jint.Tests.Runtime
             Assert.Equal(-11 * 60 * 1000, result);
         }
 
+        [Fact]
+        public void EmptyStringShouldMatchRegex()
+        {
+            RunTest(@"
+                var regex = /^(?:$)/g;
+                assert(''.match(regex) instanceof Array);
+            ");
+        }
+
+        [Fact]
+        public void ShouldExecuteHandlebars()
+        {
+            var url = "http://cdnjs.cloudflare.com/ajax/libs/handlebars.js/2.0.0/handlebars.js";
+            var content = new WebClient().DownloadString(url);
+            
+            RunTest(content);
+
+            RunTest(@"
+                var source = 'Hello {{name}}';
+                var template = Handlebars.compile(source);
+                var context = {name: 'Paul'};
+                var html = template(context);
+
+                assert('Hello Paul' == html);
+            ");
+        }
     }
 }

Jint/Native/RegExp/RegExpPrototype.cs

@@ -86,7 +86,7 @@ namespace Jint.Native.RegExp
             }
 
             Match r = null;
-            if (i < 0 || i >= length)
+            if (i < 0 || i > length)
             {
                 R.Put("lastIndex", (double) 0, true);
                 return Null.Instance;